Tropical Storm Rafael, about 465 miles north of San Juan, Puerto Rico, was expected to strengthen and become a hurricane Monday, U.S. forecasters said. Rafael, with maximum sustained winds of 70 mph, was about 680 miles south Bermuda, which was under a tropical storm watch, the National Hurricane Center said in its 5 a.m. EDT advisory. The storm, moving north-northwest at 10 mph, was expected to become a hurricane later in the day, forecasters said. Rafael was expected to shift more toward the north and could approach Bermuda by late Tuesday. Tropical storm-force winds extended outward from center up to 175 miles. Raphael was expected to produce 1-3 inches of rain over the northern Leeward Islands, with isolated totals of 12 inches possible, forecasters said. The rains could cause flash flooding and mudslides. Swells generated by Rafael were expected to affect eastern-facing beaches of the Bahamas during the next few days.